Datasheet
71M6513/71M6513H
3-Phase Energy Meter IC
DATA SHEET
AUGUST 2011
Page: 24 of 104 © 2005-2011 Teridian Semiconductor Corporation
A Maxim Integrated Products Brand
WDCON[7] selects whether timer 1 or the internal baud rate generator is used. All UART transfers are programmable for parity
enable, parity, 2 stop bits/1 stop bit and XON/XOFF options for variable communication baud rates from 300 to 38400 bps.
Table 12 shows how the baud rates are calculated. Table 13 shows the selectable UART operation modes.
Using Timer 1
Using Internal Baud Rate Generator
Serial Interface 0
2
smod
* f
CKMPU
/ (384 * (256-TH1)) 2
smod
* f
CKMPU
/(64 * (2
10
-S0REL))
Serial Interface 1
N/A f
CKMPU
/(32 * (2
10
-S1REL))
Note: S0REL and S1REL are 10-bit values derived by combining bits from the respective timer reload registers. SMOD is the
SMOD bit in the SFR PCON. TH1 is the high byte of timer 1.
Table 12: Baud Rate Generation
UART 0
UART 1
Mode 0 N/A
Start bit, 8 data bits, parity, stop bit, variable
baud rate (internal baud rate generator)
Mode 1
Start bit, 8 data bits, stop bit,
variable baud rate (internal baud
rate generator or timer 1)
Start bit, 8 data bits, stop bit, variable baud rate
(internal baud rate generator)
Mode 2
Start bit, 8 data bits, parity, stop bit,
fixed baud rate 1/32 or 1/64 of
f
CKMPU
N/A
Mode 3
Start bit, 8 data bits, parity, stop bit,
variable baud rate (internal baud
rate generator or timer 1)
N/A
Table 13: UART Modes
Note: Parity of serial data is available through the P flag of the accumulator. Seven-bit serial modes with parity, such as those
used by the FLAG protocol, can be simulated by setting and reading bit 7 of 8-bit output data. Seven-bit serial modes without
parity can be simulated by setting bit 7 to a constant 1. 8-bit serial modes with parity can be simulated by setting and reading
the 9
th
bit, using the control bits TB80 (S0CON.3) and TB81 (S1CON.3) in the S0CON and S1CON SFRs for transmit and RB81
(S1CON.2) for receive operations. SM20 (S0CON.5) and SM21 (S1CON.5) can be used as handshake signals for inter-processor
communication in multi-processor systems.
Serial Interface 0 Control Register (S0CON).
The function of the UART0 depends on the setting of the Serial Port Control Register S0CON.
MSB LSB
SM0
SM1
SM20
REN0
TB80
RB80
TI0
RI0
Table 14: The S0CON Register